JP2015033681A - Waste water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a waste water treatment apparatus which uses a film having air permeability and waterproofness, and enables efficient waste water treatment in energy saving, space saving, and low cost manners even in the case of treating a large volume of waste water or waste water having a high organic matter concentration.SOLUTION: A waste water treatment apparatus 1 according to the present invention includes: waste water 3; at least one air supply part 4 which has an air take-in port 4a for taking air into the inside and supplies the air taken into the inside to the waste water 3; and at least one film 5 having air permeability and waterproofness which is stuck on the surface of the air supply part 4 so as to be located between the waste water 3 and the air supply part 4. The air supply part 4 is used by being immersed in the waste water 3 in a state where the film 5 is stuck thereon.

Description

  The present invention relates to a wastewater treatment apparatus using the action of microorganisms.

  In Japan, an activated sludge method that decomposes organic sludge substances by utilizing the action of aerobic microorganisms is often used as a wastewater treatment method. As a method for supplying oxygen necessary for the decomposition of the organic sludge substance, a combined device or a mechanical aeration device (hereinafter, these devices are collectively referred to as an aeration device) combined with a blower and an air diffuser. Is generally used. In the method using an aeration apparatus, since it is necessary to dissolve oxygen in wastewater, energy consumption tends to increase, and reduction of energy consumption is a major issue.

  As for the current situation of water pollution problems in Japan, the level of organic pollutant removal using biochemical oxygen demand (BOD) as an index has reached a level with almost no problems. However, nitrogen removal, which causes eutrophication of lakes and rivers, has not yet been adequately addressed. Therefore, development of a wastewater treatment method that can remove nitrogen more effectively is demanded.

  As described in Non-Patent Document 1 below, many methods for treating organic wastewater containing nitrogen using the action of microorganisms have been put into practical use in the past. In each method described in Non-Patent Document 1, the action of nitrite and nitrifying bacteria that can nitrify ammoniacal nitrogen to nitrite and nitric acid in an aerobic state, and nitrite and anaerobic state It uses the action of denitrifying bacteria to denitrate nitric acid into nitrogen gas. When such a function is used, since a large amount of oxygen is required for nitrification, reduction of the energy of the aeration apparatus for supplying oxygen has become a major issue.

  The conventional air diffuser is premised on the use of a blower in combination with the air diffuser. For this reason, a commonly used porous resin air diffuser has oxygen permeability at atmospheric pressure but is not waterproof. On the other hand, rubber membrane diffusers are waterproof at atmospheric pressure but not oxygen permeable. Thus, an air diffuser having both oxygen permeability and waterproofness has not been put into practical use.

    On the other hand, the following Patent Document 1 discloses a method of performing wastewater treatment by supplying wastewater into a space formed by a sheet having oxygen permeability and water impermeability.

WO2011 / 073977A1

Sewerage facility planning / design guidelines and explanation -2009 edition-P81 (published by Japan Sewerage Association)

  In the wastewater treatment method described in Patent Document 1, wastewater is treated in the space formed by the sheet. For this reason, when processing a large volume of waste water, a large-diameter and long sheet is required, and the strength and cost of the sheet become a problem.

  Moreover, when the organic substance density | concentration in wastewater is high, since there is much required oxygen amount, oxygen will run short only by the oxygen amount supplied from the oxygen permeable sheet of an outer periphery, and wastewater treatment efficiency may fall.

  An object of the present invention is to perform wastewater treatment efficiently with energy saving, space saving and low cost even for wastewater with large capacity and organic matter concentration using a film having air permeability and waterproofness. It is to provide a wastewater treatment device that can be used.

  Moreover, the limited objective of this invention is to provide the waste water treatment apparatus which can also reduce the aeration energy required for nitrogen removal.

  According to a wide aspect of the present invention, there is provided waste water, at least one air supply unit for supplying air to the waste water, and having an air intake unit for taking air into the interior, At least one film that is affixed to the surface of the air supply unit so as to be positioned between waste water and the air supply unit, and has air permeability and waterproofness, and the air supply unit includes the film. Provided is a wastewater treatment apparatus that is used while immersed in the wastewater.

  In a specific aspect of the wastewater treatment apparatus according to the present invention, the amount of air supplied from the air supply unit to the wastewater through the film can be adjusted according to the organic matter load amount or nitrogen load amount of the wastewater. .

  On the specific situation with the waste water treatment apparatus which concerns on this invention, the said waste water treatment apparatus is provided with two or more types of films from which air permeability differs as the said film.

  In a specific aspect of the wastewater treatment apparatus according to the present invention, the wastewater treatment apparatus includes two or more types of films having different areas as the film.

  In a specific aspect of the wastewater treatment apparatus according to the present invention, the wastewater treatment apparatus performs wastewater treatment through a nitrification step of oxidizing ammonia nitrogen in the wastewater to nitrite nitrogen or nitrate nitrogen. In the nitrification step, the air supply unit is used by being immersed in the wastewater in a state where the film is stuck.

  In a specific aspect of the wastewater treatment apparatus according to the present invention, the wastewater treatment apparatus includes a nitrification step of oxidizing ammonia nitrogen in the wastewater to nitrite nitrogen or nitrate nitrogen, and the sublimation after the nitrification step. Waste water treatment is performed through a denitrification step of reducing nitrate nitrogen or nitrate nitrogen to nitrogen gas using an organic carbon source and a residual organic matter treatment step of treating an excess organic carbon source after the denitrification step. In the residual organic matter treatment step, the air supply unit is immersed in the wastewater and used in the state where the film is stuck.

  In a specific aspect of the wastewater treatment apparatus according to the present invention, the wastewater treatment apparatus is connected to the air intake unit, and at least one for introducing air from the air intake unit into the air supply unit. The air flow path unit and at least one blower for feeding air into the air flow path unit are further provided.

  On the specific situation with the wastewater treatment apparatus which concerns on this invention, the said wastewater treatment apparatus is further provided with the said air flow path part, and is further provided with the at least 1 flow control valve for adjusting the flow volume of air.

  In a specific aspect of the wastewater treatment apparatus according to the present invention, the wastewater treatment apparatus includes at least two of the air supply unit, the air flow path unit, and the flow rate control valve, and each of the air supply units The amount of air introduced into the air supply section through the air flow path section can be adjusted.

  A wastewater treatment apparatus according to the present invention has wastewater, an air intake part for taking air into the interior, and at least one air supply part for supplying the air taken inside to the wastewater, At least one film that is affixed to the surface of the air supply unit so as to be positioned between the waste water and the air supply unit, and has air permeability and waterproofness, and the film further on the surface Since the air supply part is immersed and used in the wastewater in a state where it is stuck, wastewater treatment can be efficiently performed with energy saving, space saving, and low cost even for wastewater with a large volume and high organic matter concentration. It can be carried out.

FIG. 1 is a cross-sectional view showing a schematic configuration of a wastewater treatment apparatus according to the first embodiment of the present invention. FIGS. 2A and 2B are a cross-sectional view and a side view showing a first modification of the air supply unit with a film attached to the surface. FIGS. 3A and 3B are a cross-sectional view and a side view showing a second modification of the air supply unit with a film attached to the surface. FIG. 4 is a cross-sectional view showing a schematic configuration of a wastewater treatment apparatus according to the second embodiment of the present invention. FIG. 5 is a cross-sectional view showing a schematic configuration of a wastewater treatment apparatus according to the third embodiment of the present invention. FIG. 6 is a cross-sectional view showing an example of an air cathode and an anode in a microbial fuel cell. FIG. 7: is sectional drawing which shows schematic structure of the microbial fuel cell which is a wastewater treatment apparatus which concerns on the 4th Embodiment of this invention.

  Hereinafter, the present invention will be described in detail.

  The wastewater treatment apparatus according to the present invention includes wastewater, at least one air supply unit, and at least one film. The air supply part has an air intake part for taking air into the interior. The air supply unit is provided to supply air taken into the wastewater. The film is attached to the surface of the air supply unit so as to be positioned between the waste water and the air supply unit. The said film is a film which has air permeability and waterproofness. In the wastewater treatment apparatus according to the present invention, the air supply unit is immersed in the wastewater and used in a state where the film is stuck on the surface.

  In the present invention, since the above-described configuration is provided, wastewater treatment can be efficiently performed even with a large volume of wastewater or wastewater with a high organic matter concentration with energy saving, space saving, and low cost.

  In the wastewater treatment apparatus according to the present invention, compared with the conventional activated sludge method and biological denitrification method, when treating organic matter in wastewater, it is possible to greatly reduce energy consumption, and further, It can greatly contribute to oxygen reduction and environmental improvement.

  In the wastewater treatment apparatus according to the present invention, the wastewater is supplied to the wastewater through the film from the air supply unit according to the organic load or nitrogen load (organic concentration × treatment amount or nitrogen concentration × treatment amount) of the wastewater. The amount of air may be adjustable.

  The wastewater treatment apparatus according to the present invention may include two or more types of films having different air permeability as the film. Moreover, the waste water treatment apparatus which concerns on this invention may be equipped with two or more types of films from which an area differs as said film.

  The waste water treatment apparatus according to the present invention is connected to the air intake section, and includes at least one air flow path section for introducing air from the air intake section into the air supply section, and the air flow path section. It may further comprise at least one blower for sending air into the.

  The wastewater treatment apparatus according to the present invention may be further provided with at least one flow rate adjustment valve that is provided in the air flow path portion and adjusts the flow rate of air.

  The wastewater treatment apparatus according to the present invention may include at least two of the air supply unit, the air flow path unit, and the flow rate control valve. In this case, the air supply unit It may be possible to adjust the amount of air introduced into the air supply section through the flow path section.

  Further, according to a wide aspect of the present invention, there is provided a wastewater treatment method using the above-described wastewater treatment apparatus, comprising a nitrification step of oxidizing ammonia nitrogen in the wastewater to nitrite nitrogen or nitrate nitrogen, In the nitrification step, a wastewater treatment method is provided in which the air supply unit is immersed in the wastewater with the film attached.

  Further, according to a wide aspect of the present invention, there is provided a wastewater treatment method using the above-described wastewater treatment apparatus, the nitrification step of oxidizing ammonia nitrogen in the wastewater to nitrite nitrogen or nitrate nitrogen, A denitrification step of reducing the nitrite nitrogen or nitrate nitrogen to nitrogen gas using an organic carbon source after the nitrification step, and a residual organic matter treatment step of treating an excess organic carbon source after the denitrification step, In the residual organic matter treatment step, a wastewater treatment method is provided in which the air supply unit is immersed in the wastewater with the film attached.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a schematic configuration of a wastewater treatment apparatus according to the first embodiment of the present invention.

  A wastewater treatment apparatus 1 shown in FIG. 1 includes a container 2, wastewater 3, a plurality of air supply units 4, and a plurality of films 5. A film 5 is attached to the surface of the air supply unit 4.

  The container 2 is a bottomed container. The container 2 has an inflow port 2a into which the waste water 3 is introduced, and an outflow port 2b from which the treated water 6 in which the waste water 3 has been treated is discharged. Waste water 3 is placed in the container 2. Microorganisms are present in the waste water 3 in the container 2.

  The air supply unit 4 has a rectangular outer shape. The upper end of the air supply unit 4 is open to the atmosphere. The air supply part 4 has an air intake part 4a for taking air into the inside at the upper end. In FIG. 1, air is taken into the air supply unit 4 from the direction indicated by the arrow X through the air intake unit 4 a. The air intake 4 a is an opening in the air supply unit 4. The air supply part 4 has air inside. The air supply part 4 has the frame part 4b, and has air in the internal space in the frame part 4b. The frame part 4b has a rectangular outer diameter. The upper end of the frame part 4b is open to the atmosphere. The air supply unit 4 is provided for supplying air to the wastewater 3. Specifically, the air supply unit 4 is provided to supply oxygen in the air to the wastewater 3 and is an air supply chamber. Most of the air supply unit 4 is immersed in the waste water 3 except for the upper end portion. The frame part 4b preferably has a property of being excellent in air permeability in order to supply the air in the air supply part 4 to the microorganisms through the film 5.

  The film 5 has air permeability and waterproofness. For this reason, the film 5 has a property that air passes but water does not pass. Most of the film 5 is immersed in the waste water 3 except for the upper end portion.

  The film 5 is stuck on the surface of the air supply unit 4 so as to be positioned between the waste water 3 and the air supply unit 4. The film 5 is laminated on the surface of the air supply unit 4. Specifically, the film 5 is stuck on the outer surface of the frame part 4 b in the air supply part 4. The film 5 is laminated on the outer surface of the frame portion 4b. Specifically, the film 5 is stuck so as to cover the entire four side surfaces of the air supply unit 4. Below the air supply part 4, the lower end (end part) of the film 5 is joined. For this reason, in the air supply part 4 in which the film 5 was affixed on the surface, the non-permeability was ensured by the film 5 in the part except the upper end of the air supply part 4. One film 5 may be affixed to the surface of the air supply part 4, and a plurality of films may be overlapped and affixed. The air supply unit 4 and the film 5 may be heat-sealed or may be ultrasonically fused.

  The air supply unit 4 is immersed in the waste water 3 with the film 5 being stuck on the surface. Since the film 5 has air permeability, oxygen in the air inside the air supply unit 4 passes through the film 5 and moves into the waste water 3 in the immersed state. The oxygen in the air that has reached the wastewater 3 is dissolved in the wastewater 3. Since the film 5 is waterproof, the movement of the waste water 3 is hindered by the film 5 in the immersed state, and does not move into the air supply unit 4. When oxygen that has passed through the film 5 reaches the wastewater 3, aerobic microorganisms grow in the container 2, and the wastewater 3 is decomposed by the aerobic microorganisms to obtain treated water 6. The treated water 6 flows out from the outlet 2b of the container 2.

  In the wastewater treatment apparatus 1, a plurality of air supply units 4 are arranged at intervals. Specifically, in the wastewater treatment apparatus 1, five air supply units 4 are arranged at equal intervals with intervals. A film is attached to each of the surfaces of the five air supply units 4. In addition, the number and area of the air supply part 4 and the film 5 can be changed suitably. Since the amount of oxygen necessary for the treatment is determined by the flow rate of the waste water 3 to be treated and the organic substance concentration, the number and area of the air supply unit 4 and the film 5 that can sufficiently supply the necessary amount of oxygen can be appropriately selected.

  In the wastewater treatment apparatus 1, the necessary area of the film 5 attached to the surface of the air supply unit 4 can be secured by increasing or decreasing the number of air supply units 4 to be installed according to the shape of the container 2. The amount of oxygen necessary for the treatment of the wastewater 3 can be supplied to the wastewater 3.

  Microorganisms present in the wastewater 3 in the wastewater treatment apparatus 1 are supplied with oxygen that has passed through the film 5 and therefore do not require any other power. For this reason, the energy required for the wastewater treatment of the wastewater treatment apparatus can be reduced as compared with a conventional wastewater treatment apparatus using an aeration apparatus.

  In a wastewater treatment apparatus including a plurality of wastewater treatment tanks, the wastewater treatment apparatus 1 shown in FIG. 1 can be used as a wastewater treatment tank. The wastewater treatment apparatus may include a plurality of wastewater treatment tanks.

  FIGS. 2A and 2B are a cross-sectional view and a side view showing a first modification of the air supply unit with a film attached to the surface. 2 (a) is a cross-sectional view in the same direction as FIG. 1, FIG. 2 (b) is a side view seen from the outside of the main surface of the film, and a side view seen from the left side of FIG. 2 (a). It is.

  In order to supply the air in the air supply unit to the microorganisms through the film, an air supply unit 4A in which a film 5A shown in FIGS. 2A and 2B is attached to the surface may be used.

  In FIG. 2 (a) and (b), 4 A of air supply parts are arrange | positioned between the films 5A which are facing. In the wastewater treatment apparatus, the film 5A is disposed between the wastewater and the air supply unit 4A. 4 A of air supply parts have air intake part 4Aa for taking in air inside in an upper end. The air supply unit 4A includes a vertical beam 4Ab extending in the vertical direction and a horizontal beam 4Ac extending in a direction substantially orthogonal to the vertical beam 4Ab. The dimension of the vertical rail 4Ab (the dimension in the left-right direction in FIG. 2A) in the direction connecting the films 5A facing each other through the air supply unit 4A is smaller than the dimension of the gap between the films 5A. The dimension of the horizontal rail 4Ac (the dimension in the left-right direction in FIG. 2A) in the direction connecting the films 5A facing each other through the air supply part 4A is also smaller than the dimension of the gap between the films 5A. However, when the vertical beam 4Ab and the horizontal beam 4Ac are combined, the overall dimensions of the vertical beam 4Ab and the horizontal beam 4Ac in the direction connecting the films 5A facing each other through the air supply unit 4A (FIG. 2). (Dimension in the left-right direction in (a)) is substantially the same as the dimension of the gap between the films 5A. For this reason, the space | interval between the films 5A which are facing through the air supply part 4A is controlled by the combination with vertical rail 4Ab and horizontal rail 4Ac. The vertical bars 4Ab and the horizontal bars 4Ac function as spacers for the film 5A.

  The vertical beam 4Ab and the horizontal beam 4Ac have notches and can be fitted to each other. The two bars may be arranged such that their main surfaces are orthogonal to each other, or may be arranged in an oblique direction. Even when the air supply unit 4A having the film 5A attached to the surface is used, the space between the films 5A can be secured, and a sufficient amount of air can be present in the entire air supply unit 4A.

  Moreover, Fig.3 (a) and (b) are sectional drawing and side view which show the 2nd modification of the air supply part by which the film was stuck on the surface. 3 (a) is a cross-sectional view in the same direction as FIG. 1, FIG. 3 (b) is a side view seen from the outside of the main surface of the film, and a side view seen from the left side of FIG. 3 (a). It is.

  In FIGS. 3A and 3B, an air supply unit 4B is disposed between two opposing films 5B. In the wastewater treatment apparatus, the film 5B is disposed between the wastewater and the air supply unit 4B. Air supply part 4B has air intake part 4Ba for taking in air in an upper end. In the air supply unit 4B, a plurality of dot-like bars 4Bb are arranged side by side in the vertical direction and the horizontal direction. The crosspiece 4Bb is cylindrical. The dimension of the crosspiece 4Bb (the dimension in the left-right direction in FIG. 3A) in the direction connecting the films 5B facing each other through the air supply unit 4B is substantially the same as the dimension of the gap between the films 5B. For this reason, the space | interval between the films 5B which are facing through the air supply part 4B is controlled by the crosspiece 4Bb. The crosspiece 4Bb functions as a spacer of the film 5B.

  The vertical dimension (vertical direction or vertical direction) of the air supply unit is preferably 0.2 m or more, more preferably 0.8 m or more, preferably 3.6 m or less, and more preferably 2 m or less. The horizontal dimension of the air supply part (vertical direction and direction orthogonal to the thickness direction) is preferably 0.2 m or more, more preferably 0.6 m or more, preferably 3.6 m or less, more preferably 1.8 m or less. It is. When the size of the air supply unit is equal to or more than the lower limit, the number of air supply units can be further reduced, and the cost of the waste water treatment apparatus is further reduced. When the size of the air supply unit is not more than the above upper limit, the air supply unit can be more easily transported and installed. The thickness of the air supply part is preferably 0.5 cm or more, more preferably 1 cm or more, preferably 10 cm or less, more preferably 4 cm or less. When the thickness of the air supply unit is equal to or more than the lower limit, the air in the air supply unit is easily replaced appropriately. When the thickness of the air supply unit is not more than the above upper limit, the volume of the air supply unit is not excessively large, the entire volume of the wastewater treatment tank is not excessively large, and the cost of the wastewater treatment apparatus is further increased. Lower.

  The film has air permeability that allows a gas such as oxygen to pass therethrough, and has a property that prevents water from passing through (water resistance).

  The film may be used in a state in which a nonwoven fabric, a cross yarn and other films are laminated on one side or both sides as required.

  Examples of the processing method of the film include a method of forming a resin composition containing a polyolefin resin and an inorganic material into a film and then stretching the resin composition. Examples of the polyolefin resin include polyethylene and polypropylene. Examples of the inorganic material include calcium carbonate.

  Examples of commercially available films include “Selpore” manufactured by Sekisui Film Co., Ltd., “KTF” and “Excepol” manufactured by Mitsubishi Plastics, and “Porum” and “NF Sheet” manufactured by Tokuyama.

  The thickness of the air permeable waterproof film is preferably 15 μm or more, and preferably 1 mm or less. When the thickness of the film is equal to or more than the lower limit, breakage is further less likely to occur. When the thickness of the film is not more than the above upper limit, the oxygen permeability is further increased.

  Next, an example of a method for removing nitrogen contained in the wastewater 3 using the wastewater treatment apparatus 11 provided with the wastewater treatment apparatus 1 shown in FIG. 1 as a wastewater treatment tank will be specifically described with reference to FIG. .

FIG. 4 is a cross-sectional view showing a schematic configuration of a wastewater treatment apparatus according to the second embodiment of the present invention.
In the wastewater treatment apparatus 11 shown in FIG. 4, two waste liquid treatment tanks 1 and 1A are used. The wastewater treatment apparatus 11 is a wastewater treatment facility including a plurality of wastewater treatment tanks 1 and 1A. The waste liquid treatment tank 1A changes the number of air supply units 4 to which the film 5 is attached from the waste water treatment tank 1, and changes the size of the container accordingly. The wastewater treatment tank 1 uses five air supply units 4 with the film 5 attached thereto, whereas the wastewater treatment tank 1A uses two air supply units 4 with the film 5 attached thereto. ing.

  In the case of the circulation denitrification method, the wastewater treatment apparatus 11 includes a first denitrification unit 12, a nitrification unit 13, a second denitrification unit 14, and a residual organic matter treatment unit 15. In the wastewater treatment apparatus 11, the circulating liquid 16 is circulated from the rear stage portion of the nitrification unit 13 to the front stage portion of the first denitrification unit 12. A waste liquid treatment tank 1 is used in the nitrification unit 13. A waste liquid treatment tank 1 </ b> A is used for the residual organic matter treatment unit 15.

  In the first denitrification unit 12, a first denitrification step is performed in which nitrite nitrogen or nitrate nitrogen in the wastewater 3 is reduced to nitrogen using an organic carbonic acid source in the circulating liquid 16. In the nitrification unit 13, after the first denitrification step, a nitrification step of oxidizing ammonia nitrogen in the waste water 3 to nitrite nitrogen or nitrate nitrogen is performed. In the 2nd denitrification part 14, the process of reduce | restoring the said nitrite nitrogen or nitrate nitrogen to nitrogen gas using the organic carbon source 17 is performed after a nitrification process. In the residual organic matter processing unit 15, after the second denitrification step, a residual organic matter treatment step for treating the surplus organic carbon source 17 is performed. The residual organic matter processing unit 15 requires oxygen to oxidize the organic carbon source 17 remaining in the second denitrification unit 14. Conventionally, oxygen is supplied using an aeration apparatus.

  In the present invention, oxygen is supplied to the aerobic microorganisms through the film 5 by installing the air supply unit 4 with the film 5 attached to the surface in each of the nitrification unit 13 and the residual organic matter processing unit 15. it can. For this reason, no other power is required, and energy can be significantly reduced.

  In the wastewater treatment apparatus 11, in the nitrification step, the air supply unit 4 is used by being immersed in the wastewater 3 with the film 5 attached. In the residual organic matter treatment step, the air supply unit 4 is used by being immersed in the waste water 3 with the film 5 attached thereto.

  In the wastewater treatment apparatus 11 shown in FIG. 4, the air supply part 4 has an air intake part 4a at the upper end, and the air intake part 4a is open to the atmosphere.

  FIG. 5 shows an example in which the wastewater treatment apparatus 1 shown in FIG. 1 is used as a wastewater treatment tank and applied to large-scale wastewater treatment. FIG. 5 is a cross-sectional view showing a schematic configuration of a wastewater treatment apparatus according to the third embodiment of the present invention.

  A wastewater treatment apparatus 21 shown in FIG. 5 includes three wastewater treatment tanks 1. The wastewater treatment device 21 is a wastewater treatment facility including a plurality of wastewater treatment tanks 1. Each of the three wastewater treatment tanks 1 has a plurality of air flow path portions 22 for introducing air from the air intake portion 4a into the air supply portion 4. The air flow path part 22 is connected to the air intake part 4 a of the air supply part 4. Each of the three wastewater treatment tanks 1 further includes a blower 23 for sending air into the air flow path portion 4. The blower 23 is connected to the air flow path portion 22. A blower 23 is connected to one end of the air flow path portion 22, and an air intake portion 4 a is connected to the other end. Each of the three wastewater treatment tanks 1 further includes a plurality of flow rate adjustment valves 24 for adjusting the flow rate of air. The flow rate adjustment valve 24 is provided in the air flow path portion 22. The wastewater treatment device 21 includes a plurality of air supply units 4, air flow path units 22, and flow rate control valves 24. In the wastewater treatment device 21, different air flow path portions 22 are connected to the air intake portions 4 a of different air supply portions 4, and different flow rate control valves 24 are provided in the different air flow path portions 22. Each of the plurality of air supply units 4 can adjust the amount of air introduced into the air supply unit 4 via different air flow path units 22. Further, the amount of air supplied from the air supply unit 4 through the film 5 to the waste water 3 can be adjusted according to the organic load amount or the nitrogen load amount of the waste water 3.

  Even in the wastewater treatment apparatus 21, the use of the film 5 makes the pressure loss of the blower 23 lower than when using an air diffuser or the like, so that the power of the blower 23 is small and energy saving is possible. In addition, by installing a flow rate adjustment valve 24 in the middle of the air flow path portion 22 from the blower 23 to the air supply portion 4, the amount of air supplied to the wastewater can be adjusted according to the required oxygen amount in each step of the wastewater treatment device 21. Can be adjusted.

  A flow meter 25 is installed in the air flow path portion 22. Thus, it is preferable to use the flow meter 25. By installing the flow meter 25, the amount of air flowing through the air flow path portion 22 can be confirmed.

  The wastewater treatment apparatus according to the present invention can also be applied to removal of organic substances and nitrogen by a microbial fuel cell.

  Cathodes used for microbial fuel cells include cathodes that use dissolved oxygen in the liquid and cathodes that use oxygen in the air. A cathode that utilizes oxygen in the air is called an air cathode. The air cathode has the advantage that it is only necessary to circulate air through the air cathode, and there is no need for aeration into the catholyte.

When using a microbial fuel cell equipped with the air cathode, a liquid containing microorganisms and organic substances that can grow under anaerobic conditions is caused to flow through the flow path of the gap on the surface of the anode. Further, air is caused to flow through the flow path on the surface of the air cathode, and the air is brought into contact with the cathode. At the anode, hydrogen ions (H ⁺ ) and electrons (e ⁻ ) are generated from organic substances by microorganisms. The generated hydrogen ions move to the cathode side, and a potential difference is generated between the anode and the cathode. In this state, if the anode and the cathode are connected by a conducting wire to form a closed circuit, a potential difference current flows. As a result, the electric energy flowing through the conductor can be recovered.

  FIG. 6 is a sectional view showing an example of the air cathode 51 and the anode 61 in the microbial fuel cell. In the air cathode 51, a film 5C having air permeability and waterproofness is used.

  The air cathode 51 shown in FIG. 6 includes an air supply unit 4C having a film 5C attached to the surface. An electrode substrate 52 is disposed on the surface of the film 5C opposite to the air supply unit 4C side, and a binder 53 is disposed on the surface of the electrode substrate 52 opposite to the film 5C side. The catalyst 54 is attached on the surface of the electrode base 52 opposite to the film 5C side, and the insulating layer 55 is disposed on the surface of the binder 53 opposite to the electrode base 52 side. The cathode microbial membrane 56 is disposed on the surface of the insulating layer 55 opposite to the binder 53 side.

  In the air cathode 51, oxygen that has passed through the film 5 </ b> C passes through the electrode substrate 52, the binder 53, and the insulating layer 55. For this reason, the aerobic cathode microbial membrane 56 is formed on the surface of the insulating layer 55.

  An anode microbial membrane 62 is disposed on the surface of the anode 61. In the microbial fuel cell, organic substances in the wastewater are converted into hydrogen ions and electrons by the anaerobic electrogenerated bacteria in the anode microbial membrane 62. Hydrogen ions combine with oxygen supplied from the air cathode 51 to become water.

  Also in the cathode microbial membrane 56, the organic matter in the wastewater is decomposed by aerobic microorganisms by oxygen supplied from the air cathode 51. As described above, in the microbial fuel cell, two reactions proceed simultaneously using oxygen supplied from the air cathode 51. These reactions can be controlled by changing the air permeability and area of the film 5C or by increasing or decreasing the air permeability.

  By providing the air supply part 4Ca in the air supply part 4C of each air cathode 51 and opening the upper end to the atmosphere, air naturally flows into the air supply part 4C. For this reason, oxygen can be supplied into the wastewater without using an aeration apparatus, and the power cost for aeration is unnecessary.

  FIG. 7 is a diagram showing a schematic configuration of a wastewater treatment apparatus according to the fourth embodiment of the present invention. The wastewater treatment apparatus shown in FIG. 7 is a microbial fuel cell 71.

  The microbial fuel cell 71 includes an air cathode 51 using the film 5C and can be used to remove organic substances and nitrogen in the wastewater 3.

  The microbial fuel cell 71 includes an organic matter processing unit 72, a nitrification unit 73, and a denitrification unit 74. The microbial fuel cell 71 includes a wastewater treatment tank 76 in each of the organic matter treatment unit 72, the nitrification unit 73, and the denitrification unit 74. A microbial fuel cell 71 as a wastewater treatment device is a wastewater treatment facility including a plurality of wastewater treatment tanks 76.

  In the case where only the organic matter needs to be processed, the organic matter processing unit 72 can be installed alone.

  In the organic matter processing unit 72, an organic matter treatment step for treating the organic matter in the wastewater 3 is performed. In the nitrification unit 73, a nitrification process is performed in which ammonia nitrogen in the wastewater 3 is oxidized to nitrite nitrogen or nitrate nitrogen after the organic matter treatment process. In the denitrification unit 74, after the nitrification step, a step of reducing the nitrite nitrogen or nitrate nitrogen to nitrogen gas using an organic carbon source is performed.

  In the microbial fuel cell 71, in the organic matter processing unit 72, the nitrification unit 73, and the denitrification unit 74, the air supply unit 4C is used by being immersed in the waste water 3 with the film 5C attached thereto.

  In the organic matter processing unit 72, most of the organic matter in the waste water 3 is decomposed and converted into electric energy, as in a normal microbial fuel cell. In the organic matter processing unit 72, oxygen is supplied from the air cathode 51 (air cathode for organic processing unit) through the film 5 </ b> C into the wastewater 3, and the organic matter in the wastewater 3 is electrically generated in the anode microbial membrane 62 attached to the anode 61. At the same time it is used for power generation by the fungus, a portion is degraded by aerobic bacteria in the cathode microbial membrane 56.

  For this reason, in order to increase the efficiency of power generation, it is desirable to control so that the oxygen permeation amount from the air cathode 51 does not greatly exceed the amount necessary for power generation.

  In the nitrification unit 73, ammonia nitrogen in the wastewater 3 is oxidized to nitrogen nitrite or nitrate nitrogen using oxygen supplied from the air cathode 51 (nitrification unit air cathode) through the film 5C. For this reason, in order to perform oxidation efficiently, it is necessary to supply sufficient oxygen. By adjusting the air permeability and area of the film 5C to sufficiently increase the supply amount of oxygen, the entire nitrification unit 73 becomes aerobic, and nitrite bacteria and nitrate bacteria are not only the cathode microbial membrane 56, It can also grow in the anode microbial membrane 62.

  In the denitrification unit 74, nitrogen nitrite or nitrate nitrogen is reduced to nitrogen gas. In order to advance this reaction efficiently, it is desirable to maintain an oxygen-free state. Denitrifying bacteria mainly grow in the anode microbial membrane 62. By adjusting the air permeability and area of the film 5C and reducing the amount of oxygen supplied to the air cathode microbial membrane 56 in the air cathode 51 (air cathode for the denitrification part), the film 5C is also removed into the cathode microbial membrane 56. Nitrogen can be grown.

  Moreover, about 3 times as much hydrogen donor (organic substance) as nitrate nitrogen is needed for denitrification. For this purpose, an organic carbon source 75 corresponding to a hydrogen donor is caused to flow into the denitrification unit 74. In order to efficiently perform the denitrification, it is necessary to supply the organic carbon source 75 a little more, so that organic substances often remain in a general denitrification method. However, in the microbial fuel cell, the organic matter remaining in the anode microbial membrane 62 is converted into electric energy by the electrogenerated bacteria in the anode microbial membrane 62, so that the organic matter hardly remains. For this reason, the normal biological denitrification method has an advantage that a residual organic matter treatment tank is not required.

  As the organic carbon source 75, methanol or the like can be used. Further, instead of methanol, a part of the waste water can be supplied to the denitrification section.

  As described above, the organic matter processing unit 72, the nitrification unit 73, and the denitrification unit 74 have different oxygen demand levels, but by increasing or decreasing the air permeability and area of the film 5C used in the air cathode 51, The oxygen supply amount can be controlled well.

  Since there are many types of film 5C having different air permeability, the most suitable type of film can be selected according to the required oxygen amount of each part. Specifically, it is desirable to select a type having a high air permeability for the air cathode 51 of the nitrification unit 73 and a type having a low air permeability for the air cathode 51 of the denitrification unit 74. Further, films 5C having different air permeability can be used on the inflow side and the outflow side of each part of the air cathode 51, the nitrification unit 73, and the denitrification unit 74 of the organic matter processing unit 72.

  The amount of air supplied from the air cathode 5C in each part can also be controlled by changing the area ratio between the air cathode 51 and the anode 61. Specifically, when the area ratio between the air cathode 51 and the anode 61 of the organic substance removing unit 72 is 1: 1, the area ratio between the air cathode 51 and the anode 61 is set to 2: 1 in the nitrification unit 73, for example. By increasing the ratio of the air cathode 51 to 10: 1, the amount of oxygen supplied to the wastewater can be increased. Conversely, in the denitrification unit 74, the area ratio between the air cathode 51 and the anode 61 is, for example, 1: 2 to 1:10, and the ratio of the anode 61 is increased to reduce the oxygen supply amount to the wastewater. Can do.

1 ... Waste water treatment equipment (waste water treatment tank)
DESCRIPTION OF SYMBOLS 1A ... Waste water processing tank 2 ... Container 2a ... Inlet 2b ... Outlet 3 ... Waste water 4, 4A, 4B, 4C ... Air supply part 4a, 4Aa, 4Ba, 4Ca ... Air intake part 4b ... Frame part 4Ab ... Vertical rail 4Ac ... Horizontal crosspiece 4Bb ... crosspiece 5,5A, 5B, 5C ... film 6 ... treated water 11 ... waste water treatment device 12 ... first denitrification unit 13 ... nitrification unit 14 ... second denitrification unit 15 ... residual organic matter treatment unit 16 ... Circulating fluid 17 ... Organic carbonic acid source 21 ... Waste water treatment device 22 ... Air flow path 23 ... Blower 24 ... Flow rate control valve 25 ... Flow meter 51 ... Air cathode 52 ... Electrode base material 53 ... Binder 54 ... Catalyst 55 ... Insulating layer 56 ... Cathode microbial membrane 61 ... Anode 62 ... Anode microbial membrane 71 ... Microbial fuel cell (waste water treatment device)
72 ... Organic matter processing unit 73 ... Nitrification unit 74 ... Denitrification unit 75 ... Organic carbon source 76 ... Wastewater treatment tank

Claims (9)

Waste water,
At least one air supply unit for supplying air to the waste water, the air intake unit having an air intake unit for taking air into the interior;
At least one film that is affixed to the surface of the air supply unit so as to be positioned between the wastewater and the air supply unit, and has air permeability and waterproofness,
The said air supply part is a wastewater treatment apparatus used by being immersed in the said wastewater in the state in which the said film was stuck.   The wastewater treatment apparatus according to claim 1, wherein an amount of air supplied from the air supply unit to the wastewater through the film can be adjusted according to an organic matter load amount or a nitrogen load amount of the wastewater.   The wastewater treatment apparatus according to claim 1 or 2, comprising two or more types of films having different air permeability as the film.   The wastewater treatment apparatus according to any one of claims 1 to 3, comprising two or more types of films having different areas as the film. A wastewater treatment device for treating wastewater through a nitrification step of oxidizing ammonia nitrogen in the wastewater to nitrite nitrogen or nitrate nitrogen,
In the said nitrification process, the said air supply part is a wastewater treatment apparatus of any one of Claims 1-4 used by being immersed in the said wastewater in the state in which the said film was stuck. A nitrification step of oxidizing ammonia nitrogen in the wastewater into nitrite nitrogen or nitrate nitrogen, and after the nitrification step, the nitrite nitrogen or nitrate nitrogen is reduced to nitrogen gas using an organic carbon source. A wastewater treatment apparatus for performing wastewater treatment through a denitrification step and a residual organic matter treatment step for treating an excess organic carbon source after the denitrification step,
The waste water treatment apparatus according to any one of claims 1 to 5, wherein, in the residual organic matter treatment step, the air supply unit is immersed in the waste water and used with the film attached. At least one air flow path connected to the air intake and for introducing air from the air intake into the air supply;
The wastewater treatment apparatus according to any one of claims 1 to 6, further comprising at least one blower for sending air into the air flow path section.   The wastewater treatment apparatus according to claim 7, further comprising at least one flow rate control valve provided in the air flow path unit and configured to adjust a flow rate of air. At least two each of the air supply unit, the air flow path unit, and the flow rate control valve,
The wastewater treatment apparatus according to claim 8, wherein an amount of air introduced into the air supply unit via the air flow path unit can be adjusted in each of the air supply units.

Images